Electronic Conduction Characteristics of Sol-Gel Ferroelectric Pb(Zr0.4Ti0.6)O3 Thin-Film Capacitors: Part I

Abstract

We studied the electronic conduction characteristics of sol-gel ferroelectric Pb(Zr_0.4Ti_0.6)O₃ thin-film capacitors by evaluation of time-dependent leakage current ( I-t ) and current-voltage ( I-V ) characteristics along with the dielectric properties. We found two regions in the I-V characteristics, which were (1) ohmic-like current with strong decay time dependence below about 800 kV/cm, and (2) the current with strong electric field dependence above about 1 MV/cm. The leakage current in the ohmic region strongly depended upon the measurement conditions including decay time and the current obeyed the power law of DC stressing time. The hysteresis loop shifted toward a negative field after DC stressing which implied the trapping of positive charges near the top surface. The conduction mechanism of current at high field was considered to be the mixture of Schottky emission and Frenkel Poole emission, taking the dynamic dielectric constant into account. The barrier height and trapped level were estimated to be 0.58 eV and 0.5 eV, respectively.